Threaded fasteners having a sleeved or interference fit are widely used in several applications including automobile, aircraft and general machinery. Typically, these fasteners are installed into a workpiece thereby enabling one or more other structures to be attached to the workpiece. The type of workpiece depends on the application, and may, for example, include a stringer in an aircraft or a suspension beam in an automobile.
Installation generally involves seating the fastener in the workpiece. Seating commonly means that the fastener is frictionally fitted in the workpiece such that the fastener will not dislodge. In other words, the frictional or contact area between the surface of the workpiece and the fastener is enough to keep the fastener securely in the workpiece. One way to identify when the fastener is seated in the workpiece is when the fastener is installed far enough into the workpiece that the flanged head on one end of the fastener contacts the workpiece.
Typically, a great deal of force is required to install the fastener into the workpiece. Most fasteners, therefore, are installed into the workpiece either by pressing or by hammering. Although both of these methods provide the necessary force required, several problems exist.
One problem with pressing the fastener into the workpiece is that the fastener can easily become off-center. This can lead to incorrect installation of the fastener or, even worse, bending of the fastener. Because fastener installation usually occurs on a production line, this can lead to production delays and increased production costs.
One problem with hammering the fastener into the workpiece is that this method develops the needed force by high impact with the fastener. This high impact can do great damage to the fastener and workpiece and cause them to bend, crack or even break. Moreover, these anomalies may not be noticed during production and may lead to premature failure of the fastener.
Therefore, what is needed is an apparatus and a method for installing a fastener into a workpiece that can supply the necessary force without high impact. Furthermore, the apparatus and method should be able to install the fastener reliably and safely without the danger of bending, cracking or breaking the fastener or workpiece. The safety and reliability of this apparatus and method would increase yield and quality, decrease production time and thereby decrease production costs.
Whatever the merits of the aforementioned tools and methods for installing fasteners, they do not achieve the benefits of the present invention.